Thin layer chromatography has become increasingly important in the detection and analysis of filterable materials in liquids and gases in recent years. Both from a military standpoint and in industry, the analysis of liquids and gases has become a major concern. On the one hand, the analysis of liquids and gases on and off the battlefield during warfare is necessary to prevent the unnecessary loss of life while, on the other hand, ecologically, the analysis of gases and liquids for purposes of preventing the pollution of natural resources and injury to humans, animals and vegetation cannot be of more importance.
Thin layer chromatography consists of dividing substances into zones on a thin layer of adsorbent utilizing minute amounts of the substance. The substance is placed on the end of a strip of material which usually contains an adsorbent and that end of the strip is placed in a solvent which has been preselected by virtue of its ability to separate out various components of a particular substance. The substance is separated and emerges as a spot on the adsorbent which can be detected using a number of different known techniques.
Common practice for the analysis of liquid or gaseous samples has been to filter the sample in order to collect the filterable components thereof. Although some samples can be analyzed directly on the filter, many samples are too complex to analyze directly or a particular interference in the analysis of a component of interest may be present on the filter thereby also preventing direct analysis. In such instances, the sample must be removed from the filter and then redeposited for the required thin layer chromatography. As a result, samples are often lost, mishandled or contaminated thereby making analysis difficult and oftimes necessitating the taking of a second sample. Marginal success until the present process invention is evidenced by the Silvestri Patent, U.S. Pat. No. 4,033,720 which involves the use of an overlapped joined filter and absorbent means. It is now assigned to the same assignee as the instant application.